Doutre

   Even though the Wrights had concluded that aeroplanes should be stabilized by direct pilot control, many French designers kept searching as late as 1914 for automatic stability. This fruitless quest led to various curious inventions as well as to the Concours de Securite of June 1914.
   The only automatic stabilizer with any commercial success was invented by a lawyer, and was based on the pressure of the airflow against a steel plate. Doutre assumed the aeroplane flew level at a constant speed, and his device would counteract only gusts or engine failure. When the aeroplane slowed down, the stabilizer effected a nose-down attitude; and if the speed then increased dangerously it brought the machine back to a less dangerous course. The Doutre Stabilizer was claimed to have little inertia, and thus could respond quickly and accurately.
   On 3 April 1911 the Societe des Appareils Aeriens (SAAD) Doutre was founded; Doutre contributed a Maurice Farman equipped with a Pharabet motor and the Doutre Stabilizer. The firm announced that it had sold 100 Stabilizers in 1913, but it was much more reticent about its own aircraft production; a sketch of a Doutre tandem biplane appeared in Jane's All the World's Aircraft, but it may not have been actually built. An aeroplane fitted with the Stabilizer was sold to Spain in May 1912; it was probably a Doutre. The firm offered designs of 1, 2, and 3 seats powered by 50 - or 70 hp Renaults; at the 1912 Exposition it displayed a 70 hp 2-seater with "long horns" fitted with a smoothly-faired nacelle.

   (Span: (upper) 16.1 m; (lower) 13 m; length: 12.25 m; wing area: 50 sqm; empty weight: 600 kg (the stabilizer alone weighed 20 kg); speed range: 56-90 kmh; 50 or 70 hp Renault)
  
   At the end of 1912 Doutre organized a flying school at Compiegne on the airfield of Corbeaulieu; Martinet and Legagneux were the managers and Didier the chief pilot. It is likely that not all the school's machines were Doutres. In 1913 the firm designed a lateral stabilizer which was tested by Didier; that summer 2 other Doutres were tested, one of them an aerobus for 3 or 5, fitted with a 100 hp 10-cylinder Anzani. One Doutre was flown with a radial engine, perhaps the same aeroplane that appeared in the Salons; its stabilizer had been lightened. The second was a military 2-seater with the pilot sitting at the rear of the nacelle; it was reported similar to the first one but without the horned skids; this one showed a wind-driven propeller set on the top wing.